Automatic variable transmission mechanism



Aprirl., 1930. w. PITT 1,752,755

AUTOMATIC VARIABLE TRANSMISSION MECHANISM Filed July 12,` 1928 2 Sheets-Sheet l BY f Me A TORNEY April l, 1930. W PITT 1,752,755

AUTOMATIC VARIABLE TRANSMISSION MECHANISM Filed July l2, 1928 2 Sheehs-Sl'xeel 2 NVENTOR Patented Apr. 1, 1930 l WIIZLIAM PITT, or BROOKLYN, NEW YORK i AUTOMATIC VARIABLE TRAnsMrssroN MEcHAnIsM I' v 'Application filed July 12,'

This invention relates to automatic variable transmlssionmechanism.

Pursuant -to my invention, variable speed' and corresponding torque are `automaticallyprovided by the yassembly of two or more planet gears carried by a suitable casing-in v combination with acentral gear and suitable 4centrifugal means, whereby upon 'the driving rotation of the motor shaft under control of an accelerator or other suitable controlling Vso means, the rotation of the propeller shaft of the automobile orequivalent is automatically varied in speed and at corresponding torque. e l

In the instances of use of my transmission device for stationary motive machines, a similar control of the driven'member is effected by the operation of thel speed. controlling` means or equivalent controlling device. f

My present inventionl is an'improvement overthat set forth and described in my copending application, Ser. No. 176,355, filed March' 18, 1927, and entitled Transmissionfor automobiles.

A preferred form of my invention com'- prises a casing, a set of planet gears, each gear having a shaft rotatively mounted in said casing, a central or sun gear driven by the motor shaft and meshing with said set of said planetgear shafts, a second set of planet gears rotatlvely fixed on said planet gear shafts, a` second central or s un gear for actuating the driven shaft and meshing with said second set of planet gears respectively.

My present invention is an improvement over that set forthk and described in my copending application, Serial No. 17 6,355, filed March 18, 1927, and entitled v Transmission for automobiles, in that the centrifugal devices preferably provided for in my present l invention are not directly mounted upon the planet gear `shafts as isset-forth in my aforesaid co-pending application, but are indirect,- ly mounted by means of crank and link connections therewith. Also, preferably, thecentrifugal device for any one planetgear shaft is connected by a link with an associ- 'ated planetary` gear shaft. v

It is advantageous for gear reduction to also is preferablyassociated with a momenplanet gears, a set of centrifugal devices for- 1928. Serial No. 292,144.

employ the aforesaid secondv central or sun gear, i. e. forvdriving the driven shaft, of

greaterdiameter as compared with the afore- /said iirst'central gear, and accordingly associated with planet gears of the aforesaid second set of correspondingly less diameter as compared with the said first set..`

My invention is advantageously utilized in combination with suitable control means for eecting the rate of rotation ofthe propeller planet gears of the aforeshaft or other drivenmemben'and for at- I taining neutral position rlvlngfreverse drlve. v

The assembly ofmy transmission lmeans and also forA de,-

tumdevice as in the form of a fly Wheehv `Further features and objects of the inven,

tion will be morefully understood from .the following detail description .and the acQmpanying drawings, in which- 1g. 1 is arcentral' vertical sectional elevation of showing and Fig. 2 is a sectional of Fi 1.

Re erring to Figs. l1 and 2, the regulation a preferred form of my invention,

elevation Online 2 2,

or other approved automotive motor is indi-'f' cated at 10, the main motor shaft is indi-` cated at 11 and themotor fly wheel at 12. My variable transmission device may be associated with such automotive motor 10I by securing to the posterior side of the fly Wheel 12 the shaft 13 oftheherein termed first central'or sun gearf14. Such securement may be the use of two sets of planet gears;

had by a hollowbracket 15 removably aliixed yby the tap bolts 15.1 terior side 12a of the fly Wheel 12, said bracket 15 being removably Secured to the. anterior end 13a of the shaft 13Y by means of the Wedge within the hollowed pos- .Q

clamping portion' 11dreceiving the tapered shaft end 13a in co-action with the nut 17 meshing with the screw at thel terminal of the shaft end-13a.

through the thrust bearing 18 disposed in the anterior wall 19 of the transmission casing 20. V'lfhe aforesaid first central or sun gear 14 may be splined or otherwise fixedto ap- The body4 portion of the shaft 13 extends proximately the central or sun portion of its shaft 13, and the posterior portion `13b of the shaft 13 is-.jo'urnaled in the` bearing 21 disposed within and carried bythe bearing housing 22. The bearing housing 22 is secured at its posterior portion 22a or may form a part of the shaft 23 of the herein termed second central or sun gear 24, as .will appear more fully herein-- after. The anterior portion 22b of the bearing housing 22 is preferably freely journaled, on a thrust bearing, which is disposed between the bearing housing 22 and the central portion of the shaft 13, and closely adjacent to the first central or sun gea-r 14.

Meshing with the aforesaid first central gear 14 is a set of gears,y say two in number,

respectively designated 26, 27, see also Fig. 2;

said gears 26, 27 are herein termed the first set of vplanet gears. Each shaft 28fof said. planet gears 26, 27 is suitably rotatably mounted at its opposite ends within the casing as by means of thebearings 29, 29, disposed in suitable openingsv in the anterior wall 19 of the transmission casing 20 and by means of the oppositely disposed bearings 30, 30, disposedin suitable openings in the posterior wall 31.0f the `transmission casing 20. The anterior wall 19-and the posterior wall 31 of the transmission casing 20 are preferably bolted to adjacent edges of the transmission casing 2O to provide for removab'ility of the saine. The transmission casing 20 is` conveniently of hollowcylindrical formation. The shaft 23 of the second central gear 24 is journaled in the bearing 33, carried in the central opening 34 of the posterior wall .31 of the transmission casing 20. y y It V`will be observed that the bearing 18 of the shaft 13 of the first central gear 14 is disposed within the central opening 35 of the anterior wall 19 of the transmission casing 20. The annular gland nuts 36, 37 with suitable packing are provided about the shaft 13 and the shaft 23 respectively, to seal the bearings 18, 33, respectively and the interior of the transmission casing 2O from entry of dust and from the leakage of lubrin cant therefrom. Splined or otherwise fixed to the respective gear shafts 28 is the second set of planet gears corresponding to the foresaid first set of planet gears, and o f corresponding number, in this instance, two; the second set of planet gears are respectively designated 38, 39, see Fig. 2. i f

Associated withv said` planet shafts 28 and acting in' common with'the corresponding gears of the first and second sets of planet gears are centrifugal devices, shown in the form of -weighted masses 40.l Each such Weightedmass 40 is preferably associated with itsplanet gear shaft 28 through the intermediation of a crank 28a located say at the central portion of each shaft 28;, each It is advantageous for gear reduction to select the second central ear 24 of greater diameter as compared wit the first central gear 14 and to associate the gears 38, 39 with the second set of planet gears of correspondingly reduced diameter for respectively meshing with the second central gear 24.

The posterior end of the shaft .23 of the second central gear 24 is suitablyconnected to the propeller shaft 42 or equivalent of the automobile, or other propeller vehicle, or the like. When my invention is employed for aeroplanes, motorboats or the like, the propeller shaft 42 is connected to a suitable propeller or equivalent for propulsion of the same.

I prefer to provide the posterior shaft 23 or equivalent with any suitable form of iiywheel or other inertia. device, such as the weighted cylindrical or disk wheel 43, which may be made of cast iron.

To provide for the propulsion of the automobile or other vehicle at will either in a forword direction or in a rearward diretion,

for one positionof such lever, say the dash` `and dot position 44a representing the reverse position the shaft 23 of my transmission means is connected through suitable reversing gearing with the propeller shaft 42. The opposite position 44h, shown in dot and dash outline in Fig. 1, represents the forward position of the lever 44, whereby the shaft 23 of my transmission device is connected bya clutch (notshown) or equivalent directly with the propeller shaft 42.

' The f ull outline position 44 shown in Fig. 1 representsthe neutral position of such direction 'lever in which position the shaft 23 of my transmission device is disconnected from the propeller shaft 42. It is advantageousforengine testingpurposes and for other purposes to effect the disconnection between my transmission means and the propeller shaft.

I provide for suitable control means for effecting the quiescence of the posterior shaft 23 of my transmission means in the interim 'o f movement of my direction lever 44 from neutral to reverse preparatory to bringv ing into mesh a suitable gear on my transmission shaft 23 with the reverse gearing, and also during the interim of movement of my direction lever 44 from neutral to forward preparatory to clutching the transmission shaft 23 with the propeller shaft 42.

As one form of such control means oper ated by the lever 44 I employ brake-band sections 45, cooperating with the fly wheel 43, or equivalent and combined with a multiple cam v46 secured to ther shaft 47 of' the direction `lever 44 and cooperating with the rock lever 48 or equivalent means mounted on the stud shaft 49v for operatingthe brake band sections 45. For the neutral position 44 of the lever 44, as shown in Fig. 1, the cam de-l pression 50 receives the roller 51 of the rock lever 48,4 the extent of such cam depression relative to the effective radius of the cam plate 46on the shaft 47 provides for the movement of the brake band sections 45 under their usual releasing spring means to non-breaking position.` -However, upon shifting forward the lever 44 to its reverse position 44a the cam rise 52a encounters the roller 51 and Vrocks the rocker arm 48 against its return spring 53 to set the brake band sectionsA in braking position for the period of transit of the roller relative to the cam rise 52a. Upon the roller 51 attaining the cam depression the rocker arm 48, rocked by its spring 53 in return direction, moves the brake band sections 45 to non-braking position.l

Similarly, the cam rise 52b depresses the cam roller 51I and the rocker arm 48 Ato set the brake band sections 45 in braking position'for the period of effective transit of the roller lrelative to themcam rise 52h, and upon the control lever 44 attaining its position 44b for forward connection of the posterior shaft 23 of my' .transmission means l with the propeller shaft' 42 and cam depresvvterior 'shaft 13 of my transmission means to be likewise rotated. Let us assume that the rotation of the engine shaft and therefore of the anterior transmission shaft 13 is in clockwise direction. t By\ reason lof the enmeshing of the first central gear`14 with its s et of planet gears 26, 27, the planet gears 26, 27 are rotated counter-clockwise. i It isborne in mind that said second set of planet gears38, 39 mesh with the second central gear 24, 'which under the conditions assumed tends to be held sta- A hatched outline.

tionary by the braked position of the propeller shaft or tractivewheels.

In such circumstances, the rotation of the motor sha-ft 11 effects the bodily and individual axial rotation of the gears 26,27 and 38, 39.

of the respective first and second sets of planet gears and of the transmission casing 20 about the central aXis of the transmission casing 20 in counter-clockwise direction.'

At such idling speed, the centrifuga-l masses 40 effectonly anegligible resistance to the rotation of therespective gear shafts 28, 28.

During this stage, the centrifugal devices have a general radial ,movement as well as their bodily rotationas aforesaid, which general radi al movement is effected by the rotations of the crank' 28a.

Upon 'now releasing the automobile brake to thereby free the propeller shaft and the tractive Vwheels andiupon depressing the foot accelerator to derive an increasing engine speed, such increasing engine speed causes a corresponding increasing speed of rotation of the anterior shaft 13 and the first central gear 14 in a clockwise direction, and the first central gear14 in turn causes an increasing speed of counter-clockwise rotation of the first set of planet gears 26, 27, and the second set of planet gears 38, 39, which mesh with.

-the second central gear 24; the second central gear 24 during this period is held stationary bythe inertia of the vehicle, causing counterclockwise bodily rotation of the casing 20.A This bodily rotation of the casing 20 causes centrifugal force to act against the radial movement ofthe centrifugal devices 40, 40, during the period of their movement toward the axis of the shafts 13, 23; the above mentioned centrifugal force varies with the speed of bodily rotation of the casing 20,. therefore with an increasing engine speed and increasingl clockwise torque applied to the second central gear 24. y

By reason of the mounting-s provided forthe centrifugal devices 40, 40, the movements ofthe same are restricted to certainregions respectivelyy of the relatively small areas as ,l i

compared with the centrifugal deviceswhen mounted directly upon the planet gear shafts,

as is set forth in my aforesaid co-pending application Ser. No. 176,355. Such advantageous result is derived by the provision of the crank shafts 28ato which each centrifugal device is directly pivoted and further tothe employment of the links 40d connecting each centrifugal device 40 to the4v zo-operating planet gear shaft. The limited range of movement of the centrifugal 'devices-is, illustrated in Fig.` 2, namely, by the one extreme position shown in dash and dot outline and the other eXtreme-positionA shown in each centrifugal device in this instance does not fly about its planet gear shaft as an axis and therefore no force is applied by the cen- It will be observed that' y trifugal device tending to .ur e its planet gear shaft about its own'axis. oWever, each centrifugal device 40 exerts its full force by reason of its rotation bodily about the axis of the casing 20, together with the momentum of the casing and therewith the planet gearing and the respective planet gear shafts, all bodily about the axis of the casing. Such rotations as may be effected bythe centrifugal devices, about their crank shafts 28 introduce a fluctuation in the total rotational effect of each planet gear shaft upon the ultimate driving effect by the engine shaftl upon the propeller shaft but such fluctuationsare substantially overcome by the .use of al fly wheel 43, as is set forth more fully hereinafter.

Assuming the vehicle to be at rest, the aplication of increasing torque transmitted rom the engine shaft to the propeller shaft 42*- sets the vehicle into motion as ra idlyfas the engine speed develops under the oad imposed upon it. rlhis drive corresponds to a 10W gear drive used at the present time with ate with a one to one drive, the accelerator pedalis permitted to rise to cause decreasin engine speed While the propeller shaft spee remains approximately the same, so that when the anterior shaft 13 and the posterior shaft 23 reach substantially the same speed, a clutchelike connection becomes effective between the anterior shaft 13 and the posterior shaft 23 by the centrifugal force maintaining the centrifugal devices 40, in their bodily tion of the planet gears. The above centrifugal force is novir maintained by thebodily clockwise rotation of the casing 20. When theaccelerator is permitted to rise, as just described, the counterclockwise rotationof 4the casing 20 comes to an end and thereafter the casing 20 rotates clockwise at engine speed When the above described high speed or one to one drive is reached. When a grade is en- `countered that requires a more advantageous Vgearing to enable-vehicle to ascend considering it to be inthe one to one driverstate, the

increasing load imposedrupon the engine causes a drop in the enginespeed andthis Adrop causes a falling off of thecentrifugal force that maintained the-clutch-like connecy drive of the motor is effected by thebodily and individual rotation of the planet gears 26,27, 38, 39 and the transmission casing 20.

To increase the centrifugal' effect of such centrifugal device 40, the same may be of hollow metal and contain mercury orlike material of relatively high specific gravity.

.To reverse the drive of the automobile, the direction lever 44 is 'shifted to its reverse position 44, with the intermediate braking of the posterior shaft 23 by the brake bandI casing 20 and the individual and bodily rota-V tion of the enclosed gears 26, 27, 38, 39 and centrifugal devices 40.

v The transmission casing 20 may be suitably rotarily supported, as by means` of brackets or the like extending from the chas- 'sis frame and supporting suitable bearings automobiles generally. When the vehicle atf tains the speed at which it is desired to oper-,

outward rotation, thereby preventing rota-.1

.planet gear shaft. x

for receiving the hubs 34 and 35, see Fig. 1, which in such instance are suitably enlarged and arranged.

` Whereas I have described my invention by reference to specific forms thereof, it will be understood that many changes and modifications may be made Without departing from the spirit of the invention.

I claim. v l

l. A variable transmission mechanism for automobiles and the like comprising a casing, a sun ear mounted -in said casing, a driving `sha t mounted in said casing and secured to said sun gear, planet gears meshing with said sun gear, shafts for said planet gears revolvably mounted in said casing, a secondset of planet gears respectively secured to said planet gear shafts, a second sun gear meshing respectively with -said second set of planet gears, a driven shaft secured to said second sun'lgear and rotatably mounted in said casing, said planet gear shafts in cluding crank shaft portions, a set of centrifugal devices corresponding to said planet gearshafts, a link for each centrifugal device pivotally connecting its centrifugal device With one of saidcrank shaft portions and a link for each centrifugal device connecting its centrifugal device with an 2. A variable transmission mechanism for associated j 1515 ,automobiles and the like comprising a casing,

f said sun gear, planet gears meshing with said lplanet gear shafts, a second sun gear mesh-I a sun gear mounted in said casing, a driving shaft mounted 1n sald casing and secured to sun gear, shafts for said planet gears revolvably mounted in Said casing, a second set of planet gears respectively secured to said ing respectively with said second set of planet gears, a driven shaft' secured to said second sun' gear and rotatably mounted in said casing, said-planet gear shafts including crank shaft portions, said planet-gear shafts being two in number, a pair of centrifugal devices,

links connecting said centrifugal devices respectively with said pair of crank shaft portions and a link connecting each centrifugal device with the associated planet gear shaft. In testimony whereof I have signed this specification this 18th day' of June, 1928.

WILLIAM PITT. 

